I think it depends on how friendly the lecturer is.
I've asked on many occasions, however, that has usually been to confirm/find out if i had the highest mark and they seemed more than happy to tell me. Not sure how helpful they are if you're not within the top handful, particularly if the unit has hundreds completing it.
Also, the lecturers i asked were ones that knew me as in knew who i was, not just recognised my name from class rolls, so they're probably more likely to help if they know you.
Hope you find out